Kauffman Audio Appliances - Aurora Overdrive

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
Post Reply
User avatar
soulsonic
Old Solderhand
Information
Posts: 3880
Joined: 27 Jun 2007, 03:38
my favorite amplifier: Traynor YVM-1
Completed builds: too many!
Location: Morgantown, WV
Has thanked: 183 times
Been thanked: 468 times
Contact:

Post by soulsonic »

Getting this thread started. Will come back to it later this evening and update with schematic and pics. I have the neat CAD drawing almost complete, so please be patient for a couple hours, will upload after I'm home from work.
A Kauffman Audio Appliances Aurora overdrive just landed on my bench. I've finished the trace and it's a Timmy with a few parts changed - mostly to the detriment of what makes the Timmy sound great, IMO.
Quick rundown of core differences:
  • JRC4558 opamp instead of 4559
  • Input resistor changed from 510K to 470K
  • Cap to vbias in feedback loop of first stage changed from 39nF to 33nF
  • Bass Cut control removed
  • Diode switches and associated diodes removed, just has the four clipping diodes, arranged the same as Timmy
  • Hi Cut control changed to 100K linear - this is almost unusable to my ears, with the good range only the upper 25% of the rotation
  • Volume control changed to 500K audio - this makes the output very low and muddy at any setting other than 90%+
  • Power supply capacitor changed from 47uF to 10uF
That's pretty much it...

Don't let the slick video fool you. Inside is the typical sloppy perfboard with spaghetti wire mess and electrical tape we've come to expect from bootweekers who try to cash in on the madness with little knowledge of how to build quality products. Not surprised this guy's business didn't last long. Can't tell whether the footswitch is going bad, or maybe it just needs to be re-soldered, because it looks like some wires are barely attached.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

User avatar
soulsonic
Old Solderhand
Information
Posts: 3880
Joined: 27 Jun 2007, 03:38
my favorite amplifier: Traynor YVM-1
Completed builds: too many!
Location: Morgantown, WV
Has thanked: 183 times
Been thanked: 468 times
Contact:

Post by soulsonic »

Schematic:
Kauffman Aurora 03-23-2023.JPG
Yep, pretty familiar looking.

And gutshots:
IMG_20230323_225735.jpg
IMG_20230323_225427.jpg
IMG_20230323_225041.jpg
IMG_20230323_224957.jpg
IMG_20230323_224937.jpg
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

User avatar
soulsonic
Old Solderhand
Information
Posts: 3880
Joined: 27 Jun 2007, 03:38
my favorite amplifier: Traynor YVM-1
Completed builds: too many!
Location: Morgantown, WV
Has thanked: 183 times
Been thanked: 468 times
Contact:

Post by soulsonic »

Oh, and regarding the demo video at the top. I honestly have no idea how they made it get that sputtery fuzzy splatty distorted tone starting at 02:04. The pedal I have sounds absolutely nothing like that at those settings, or at any settings. It seriously sounds like they recorded it by plugging the output directly into a sound card and didn't bother to use any amp or speaker simulation after.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

User avatar
culturejam
Old Solderhand
Information
Posts: 4062
Joined: 24 Feb 2008, 05:59
Has thanked: 433 times
Been thanked: 563 times
Contact:

Post by culturejam »

Power supply capacitor changed from 47uF to 10uF
But WHY????? :scratch:

User avatar
soulsonic
Old Solderhand
Information
Posts: 3880
Joined: 27 Jun 2007, 03:38
my favorite amplifier: Traynor YVM-1
Completed builds: too many!
Location: Morgantown, WV
Has thanked: 183 times
Been thanked: 468 times
Contact:

Post by soulsonic »

culturejam wrote: 26 Mar 2023, 00:46
Power supply capacitor changed from 47uF to 10uF
But WHY????? :scratch:
You know, for more "bloom" :lol: :lol: :lol: :lol: :lol:
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

User avatar
culturejam
Old Solderhand
Information
Posts: 4062
Joined: 24 Feb 2008, 05:59
Has thanked: 433 times
Been thanked: 563 times
Contact:

Post by culturejam »

soulsonic wrote: 26 Mar 2023, 01:06 You know, for more "bloom" :lol: :lol: :lol: :lol: :lol:
:shred:

Post Reply